Summer may be sweltering where you are, but in Antarctica, it's winter! (Doesn't that make you feel cooler just thinking about it?) In temperatures as low as minus 50 degrees Fahrenheit, Antarctic Emperor penguins must huddle together in large numbers to stay warm.
Now physicists have discovered, using time-lapse video, that the penguins don't just huddle in place, but constantly shuffle their positions step by step, creating a giant wave pattern. This mass motion lets birds on the outside of the group keep moving towards the inside, where it's warmer.
Want to learn more about the physics of wave motion? Check out activities like Wave Machine and Big Wave in the howtosmile.org collection.